1. Field of the Invention
The present invention relates to the field of agricultural machinery, and more particularly to couplers for joining upper and lower augers in folding grain conveyors as used on grain carts, combines, and other equipment used in the harvesting and transportation of grain.
2. Description of the Related Art
Grain carts, combines, and other equipment used in the harvesting and transportation of grain often utilize an auger type grain conveyor for unloading the grain from an onboard bin or hopper and transferring it to another location, such as a truck or storage bin. Grain conveyors on mobile equipment often must be made so that they can fold for transport and then be extended for use. Folding conveyors generally have upper and lower sections pivotally connected by some type of hinge. The unfolding operation is often accomplished remotely by means of hydraulic actuators. Each joint where a conveyor folds requires the use of an auger coupler to join the upper auger to the lower augers.
In order to function properly, an auger coupler used in a folding conveyor must perform two functions; it must align the two augers and it must drive the upper auger by transferring rotational movement from the lower auger to the upper auger. The alignment function is generally performed by a centering pin or pilot shaft connected to one of the augers which engages a receiver in the other auger. The centering pin usually has a tapered or hemispherical end which helps guide the pin into the receiver as the conveyor unfolds. The drive function of the auger coupler can be performed in a wide variety of ways, but is generally accomplished by an arrangement of pins or teeth on the adjacent auger ends which interlock to transfer rotational movement from one auger to the other.
A very simple auger coupler is disclosed by U.S. Pat. No. 3,550,793 issued to Martin A. Davidow and assigned to the J. I. Case Company. This coupler is centered by an upper auger equipped with a tapered end which engages the hollow center tube of the lower section. The drive function is performed by a single longitudinally mounted pin mounted to the lower auger tube which engages a transversely mounted pin on the upper tube. A somewhat similar design is disclosed by U.S. Pat. No. 3,337,068 to J. L. Meharry which utilizes a longitudinally mounted pin on each auger to drive the upper auger. While having the advantage of simplicity, these designs would be prone to breakage or bending of the drive pins, resulting in failure of the conveyor.
An auger coupler which appears to be more durable is disclosed by U.S. Pat. No. 3,670,913 issued to Robert S. Reaves and assigned to the Allis-Chalmers Manufacturing Company. In this design the lower auger is equipped with a socket member having a central pilot shaft receiver and an internal drive flange. The upper auger includes a tapered pilot shaft which is encircled by a spiral-shaped driven flange. The drive flange and driven flange engage each other to drive the upper auger as the pilot shaft enters the receiver. One problem with this design is that grain or other debris could easily collect in the socket member and interfere with proper engagement of the coupler. Accumulation of debris in the coupler would necessitate the operator to manually clean out the coupler before the conveyor could be operated. This extra clean-out step would be time consuming and even potentially hazardous as it would expose the operators hands to the working parts of the auger.
It is apparent that there remains a need for a strong, durable auger coupler that is capable of engagement despite an accumulation of grain or debris on the components of the coupler.
The present invention comprises an auger coupler for a folding grain conveyor which operates to connect the upper auger to the lower auger. The coupler is specially adapted to work effectively despite an accumulation of grain or debris on the components of the auger coupler. The auger coupler has two parts; a lower or drive member which is secured to the lower auger and an upper or driven member which is secured to the upper auger.
The drive member includes an input shaft which is adapted to be connected to the lower auger. On an opposite end of the drive member from the input shaft is a pilot shaft having a tapered end or centering cone designed to help align the drive member with the driven member. The pilot shaft is in axial alignment with the input shaft. Surrounding the pilot shaft is an annular first thrust bearing surface. The thrust bearing surface engages a similar surface on the driven member and thereby controls the axial spacing between the two members. Spaced outwardly from the thrust bearing surface of the drive member is an annular row of drive teeth. The drive teeth project axially upwardly from an annular base surface which is parallel to and concentric with the thrust bearing surface. The drive teeth each have an engagement surface and a sloping alignment surface opposite the engagement surface.
The driven member includes an output shaft which is securable to the upper auger. On an opposite end of the driven member from the output shaft and in axial alignment with the output shaft is a receiver sized and shaped to accept the pilot shaft of the drive member. The receiver is surrounded by the driven member""s thrust bearing surface. Spaced radially outwardly from the thrust bearing surface is an annular row of driven teeth which are structurally identical to the drive teeth. The driven teeth project axially downwardly from a tooth base surface which is parallel to and concentric with the thrust bearing surface.
As the conveyor is unfolded, bringing the upper and lower augers into axial alignment, the driven member comes into engagement with the drive member to transfer rotational movement from the lower auger to the upper auger. As the two coupler members come together, the tapered end of the pilot shaft guides the pilot shaft into the receiver, which axially aligns the driven member with the drive member. The alignment surfaces of the teeth help bring the teeth into proper orientation so that the tooth engagement surfaces of the drive and driven members can engage each other.
When the coupler members are fully engaged the thrust bearing surfaces of the two members are in contact with each other. This contact between the thrust bearing surfaces holds the drive and driven teeth in spaced relation along the axis of rotation, such that a first set of clearance gaps are formed between the lower extremities of the driven teeth and the drive tooth base surface and a second set of clearance gaps are formed between the upper extremities of the drive teeth and the driven tooth base surface. These first and second sets of clearance gaps allow the coupler driven member to engage the coupler drive member despite an accumulation of grain or debris on either of the coupler members.
The auger coupler also includes an automatic clean-out feature. Any grain or debris which has collected in the clearance gaps will be spun out of the clearance gaps when the coupler begin to rotate. In addition, the clearance gaps communicate with the annular space left between the rows of teeth and the outside edges of the thrust bearing surfaces, allowing any grain or debris which has accumulated in the annular space to be spun out as well.
The principal objects and advantages of the present invention include: providing an auger coupler for joining upper and lower augers of a folding grain conveyor; providing such an auger coupler which is capable of transferring rotational movement from the lower auger to the upper auger; providing such an auger coupler which will engage despite an accumulation of grain or debris on the auger coupler; providing such an auger coupler which has an automatic clean out feature; providing such an auger coupler which is strong and well balanced; and providing such an auger coupler which is economical to manufacture, efficient in operation, capable of long operating life and particularly well-adapted for the proposed usage thereof.